The efficient operation of a machine frequently depends upon the proper adjustment of one or more of its machine parts. This requirement for proper adjustment has resulted in the invention of a variety of adjusting devices that move a machine part or parts to a selected position. These adjusting devices are therefore generally well known in the prior art, and include those that permit horizontal center adjustment, leveling adjustments, radial arm adjustments, and the like; in sum, adjustments for any movable machine part.
Knobs and levers are frequently used in these adjusting devices so that the adjustable machine part can be moved to its desired position by the selected movement of the associated knob or lever. Where a knob is used, this selected movement can be accomplished by rotation of the knob. It is apparent, however, that unwanted movement can also be accomplished by rotation of the knob. For example, this can result from an accidental bump to the knob. Since an exposed knob is more likely to be accidently bumped, the prior art has recognized the continuing need to protect the exposed knob. Knobs are either recessed, which can be partial or total, or covered, again either partial or total, or the like to minimize or eliminate this risk. These protective measures have not been totally successful, and often have made it very difficult for an operator to rotate a protected knob.
While the present invention can find use in any one or more of these prior art adjusting devices, it does find particular use in an adjusting device for the sights on a weapon. It is, therefore, described for use in the specific embodiment of an adjusting device or adjustment mechanism for a telescopic sight on a rifle. Usually, these adjustment mechanisms depend upon knobs that can be rotated clockwise and counterclockwise to make a desired adjustment in the sight relative for example, to elevation and windage.